The present invention concerns a multifunctional stethoscope usable on both ears and preferably fitted with a bow.
Stethoscopes are instruments for investigating sound phenomena or for auscultation of organ functions. Stethoscopes commonly in use are tube stethoscopes usable on both ears and fitted with bows; as the head-piece they have an open bell or a part closed by a membrane. In addition to mechanical tube stethoscopes, electronic stethoscopes are also available on the market. By the head-piece of a stethoscope is meant a listening spout which can be placed on the body of the patient being examined. The listening spout connected to a chest-piece from which two bow sections lead to the ears.
Whereas in the case of the tube stethoscope the acoustic signals are conducted directly from the spout placed on the body via the chest-piece and the two bow sections to the ears of the examining doctor, with the electronic stethoscope the acoustic signals are received by a microphone fitted to the head-piece, converted into electric signals, transmitted to loudspeakers at the ears and amplified there.
In addition to traditional electronic stethoscopes, special models are also known for phonocardiography. A phonocardio-graphically operating stethoscope is known, for example, from U.S. Pat. No. 4,840,183. A further phonocardiographic stethoscope which is connectable to suitable graphic recording units is described in U.S. Pat. No. 5,025,809.
Whereas in the case of stethoscopes operating phonocardiographically, heart noises caused by heart functioning are received and amplified and, if required, recorded by suitable means, electrocardiographs plot the curve structure in terms of the temporal progression of the bio-electric voltages accompanying the increase and decrease of excitation within the heart.
These bio-electric voltages are transmitted by means of electrodes attached to the body surface. The data acquired, displayed in a time sequence, forms an electrocardiogram (ECG) which shows several diagnostically relevant factors.
Finally, an oesophageal stethoscope is known from U.S. Pat. No. 5,394,880; this has a catheter which can be inserted into the oesophagus, within which catheter a cardiophonically operating microphone and several sensors are fitted. In particular, a sensor for measuring body temperature and two electrodes for electrocardiographic recording are provided here. The signals received through the catheter are transmitted via an electric lead to a plug socket which enables connection to suitable recording devices.
Whereas traditional electronic stethoscopes and known electrocardiographs are instruments which are in daily use by general practitioners, oesophageal stethoscopes are highly sensitive instruments which are used only in the clinical context.
It is the object of the present invention to provide a multifunctional stethoscope which can be used in a mobile way by the general practitioner, and which allows simple electrocardiographic investigations to be made in addition to auscultation.
This objective is met by an electronic stethoscope with a headpiece in which several sensors are arranged around the microphone, at least three of which are electrodes positioned in an Einthoven Triangle arrangement in order to obtain an electrocardiogram (ECG), and in which a display arrangement is incorporated in the headpiece for visual display of body function values obtained by the sensors, the values being collected by an evaluation unit and processed for the display arrangement.
An optimally space- and weight-saving solution is achieved if the display arrangement located in the head-piece takes the form of a liquid-crystal display. The cheapest solution is achieved if the three electrodes for obtaining the ECG are fixed inside the head-piece.
If only one of the three electrodes is fixed inside the head-piece while the two other electrodes are attached movably on the stethoscope head-piece, the Einthoven Triangle can be altered or enlarged. The greatest possibility of variation is achieved if all three of the electrodes used to obtain the ECG are made movable.
An especially preferred embodiment has the movable electrodes mounted pivotably in arms fitted to the periphery of the contact surface of the stethoscope head. In the position where they are not pivoted out they form a closed contact ring. This allows a relatively large Einthoven Triangle for the electrodes to be formed despite the use of a relatively small stethoscope head. It also yields a correspondingly informative ECG. This latter solution can be further improved by forming the pivoted arms so that they are in electrical contact with the evaluation unit only in the swiveled-out position. This prevents relatively uninformative data with regard to production of an ECG from being recorded.
The traditional stethoscope, known for approx. the last 100 years, has become the most-used diagnostic instrument of doctors because it can be used easily, conveniently and without preparation, can be always carried in the pocket or around the neck, and used without loss of time. All other instruments are separate, usually electrical devices which take up space and have to be set up, etc.
The electronic stethoscope according to the invention enlarges the previous, simple possibilities of (acoustic) diagnosis by simultaneously capturing, with equal simplicity, visually displaying and evaluating the bio-electrical excitation involved in heart activity. In this way important information on irregularities in heart frequency, so-called tachycardiae, ventricle flicker and other problems otherwise only detectable later, can be recognized straight away at the first medical examination.
The electronic stethoscope according to the invention can additionally be fitted with sensors for measuring blood pressure and/or temperature. The evaluation unit, also mounted in the headpiece, normally transmits the signals directly to the recording device. However, the signals can also be input into a data memory and only from there transmitted to a static image on the display device.